Effect of dietary protein on serum insulin and glucagon levels in hyper- and normocholesterolemic men.

This study was designed to test the effect of dietary protein on blood levels of insulin and glucagon. Twelve normocholesterolemic (less than 200 mg/dl) and 11 hypercholesterolemic greater than 240 mg/dl) healthy male subjects, 31-62 years of age, were randomly given 3 liquid test meals 1 week apart. Meals were identical except for the protein source (soybean, casein, or protein free). Blood was drawn at fasting, and 0.5 and 2 h postprandially. Insulin and glucagon levels were measured by radioimmunoassay. Hypercholesterolemic subjects had a higher (P less than 0.05) insulin/glucagon ratio (1.5) than normocholesterolemic subjects (0.7) 2 h post-prandially when fed the casein test meal. There was no significant difference following the soybean test meal. This implies that the post-prandial insulin/glucagon ratio was affected by the amino acid composition of the diet. There was a consistently higher insulin response to all test meals among hyper- versus normocholesterolemic subjects. These results are consistent with our hypothesis that the hypocholesterolemic effects of soybean protein and the hypercholesterolemic effects of casein were mediated by altered levels of insulin and glucagon.

Work function analysis of vegetarian entrée production.

Data on labor time for food production can be used as an effective management tool. It is essential for foodservice managers to know how labor time is being used (1). A continuous time study was conducted to determine total labor time for the production of eight vegetarian entrées in a hospital foodservice system. Two work areas were observed: the ingredient assembly area and the cooks' production area. Times were recorded by work function to identify how labor time was distributed. Results showed (a) observed frequency for each work function, (b) time expended in seconds per portion for each work function, (c) percentage distribution of labor time by work function, (d) total time for each employee involved in entrée production, and (e) percentage of total time in which each employee was involved in the production of each entrée. Total labor time varied by type of entrée, ranging from 39.97 to 19.33 seconds per portion. Entrées with the highest labor time required the largest amount of hand labor. A one-way analysis of variance indicated significant differences in mean labor time among the eight vegetarian entrées for direct labor time (p = .0009), and total labor time (p = .0018). No significant differences were found among entrées for indirect labor or delay time.

Effects of microwaving human milk: changes in IgA content and bacterial count.

On the basis of this study, IgA was best preserved in frozen human milk by thawing either overnight in the refrigerator or under warm running water. If either of those procedures are to be used, it is suggested that bacterial monitoring should be performed. Because current technology does not allow for accurate low internal temperature monitoring of liquids, it is concluded that use of the microwave oven for the treatment of human milk is inappropriate. However, because microwaving is as effective as holder pasteurization in killing bacteria, and because it would be less expensive and is faster, this process should be further investigated.

Separate effects of dietary protein and fat on serum cholesterol levels: another view of amino acid content of proteins.

Casein or soy protein with vegetable or animal fat were used to determine the dietary protein or fat effects and their possible interaction on serum cholesterol levels. Young, male New Zealand white rabbits with a mean weight of 2.1 kg were divided into groups of six and fed one of four different diets containing 20% of the calories as protein, 30% as fat (according to dietary guidelines for the United States) and 50% as carbohydrate. The diets contained casein or soy (lysine/arginine ratio = 2.2 or 0.9, respectively) as the protein sources with fat from either almond oil or butter. There was no significant difference in weight gain among the diet groups. Total serum cholesterol level was highest among animals fed the diet containing butter with casein (177 +/- 25 mg/dl) or soy protein (189 +/- 50 mg/dl), it was intermediate in animals fed the vegetable oil with casein (121 +/- 14 mg/dl), and lowest in the soy protein with vegetable oil group (58 +/- 12 mg/dl). There was a significant difference in serum cholesterol levels due to the protein effect when vegetable oil was used (p less than 0.05) but not with butter. There was also a significant fat effect on serum cholesterol when the diet contained soy protein (p less than 0.005) but not when the protein was casein. No significant interaction was observed between the dietary fat and protein sources on serum cholesterol levels, which suggests that dietary protein and fat independently affect the levels of serum cholesterol. Thus, dietary protein has a significant effect on serum cholesterol levels and may be a factor in the low levels of serum cholesterol observed among vegetarians and in humans of Third World countries where the diets is primarily of vegetable origin.

Cholesterolemic effects of the lysine/arginine ratio in rabbits after initial early growth.

The lysine/arginine ratio has been directly associated with serum cholesterol levels. Male, New Zealand rabbits with a mean weight of 2.1 kg were fed, ad libitum, one of three diets containing 14% vegetable oil and 20% protein from casein, soy or almonds with lysine/arginine ratios of 2.2, 0.9, or 0.3, respectively. At the end of three weeks for phase 1, the serum cholesterol level of the casein group (154 +/- 25 mg/dl, mean +/- SD) was twice the level and significantly greater (p less than 0.02) than either of the plant protein groups (soy 70 +/- 7, almond 78 +/- 6 mg/dl). During phase 2, the almond diet was supplemented with L-lysine to increase the lysine/arginine ratio from 0.3 to 3.0 while casein remained as the high, and soy the low lysine/arginine ratio control diets. Serum cholesterol levels remained high for the casein, and low for the soy groups, while lysine supplementation significantly increased (p less than 0.05) the serum cholesterol level in the almond protein group (from 78 +/- 6 to 101 +/- 10), but not greater than the casein group. Growth was similar for rabbits fed soy or casein diets throughout the study, but lower (p less than 0.02) for the almond group. Thus, growth rate was not related to the effect of dietary protein on levels of serum cholesterol. While there is a direct relationship between hypercholesterolemia and the absolute amount of dietary lysine and with the lysine/arginine ratio, the data suggest that this is only a partial explanation for the effect of proteins on the control of serum cholesterol levels.

Lacrimal testing. Age as a factor in Jones testing.

PURPOSE: A modified Jones test is used to assess whether lacrimal transit time varies with age. METHODS: The right eyes of 101 control subjects and 18 patients suspected of having lacrimal system abnormalities were tested with one drop of 2% sodium fluorescein solution. A cotton applicator was placed in the nose next to the inferior turbinate and participants were asked to lean forward. Dye passage was assessed every 3 minutes for 24 minutes. RESULTS: The results were assessed by age. In control subjects, there seemed to be a natural break in the distribution of the data at the age of 45 to 50 years. In control subjects younger than 45 years of age, 10/11 (91%) passed dye in 6 minutes or less (median = 3 minutes), whereas in those 45 years of age and older, 79/90 (84%) passed dye in 12 minutes or less (median = 6 minutes). The results were statistically significant (P = 0.0091). In contrast, patients with symptoms of epiphora due to a nasolacrimal duct obstruction had lacrimal transit times in excess of the above limits. CONCLUSION: This study confirms that the lacrimal transit time slows with age. The modification of the Jones test presented here requires a cutoff of 6 minutes in patients younger than 45 years of age and 12 minutes in patients 45 years of age and older.